Neuropsychological function in solvent-exposed South African paint makers

Neuropsychological and neurological function were investigated in 228 organic solvent exposed paint manufacturing workers in two factories. Solvent exposure was expressed as both American Conference of Governmental Industrial Hygienists 1990 Threshold Limit Value equivalents and total hydrocarbon parts per million. The World Health Organization (WHO) neurobehavioral core test battery, the Neurobehavioural Evaluation System--2 (NES-2), and the UNISA Neuropsychological Assessment Procedure (UNAP) were used to measure outcomes, and a Vibratron II was used to measure peripheral vibration sensation. Exposures were generally below the Threshold Limit Value, and no exposure effect was found. Possible explanations for this finding are discussed, including low exposure, exposure, and outcome misclassification, together with inappropriateness, nonvalidity, and relative insensitivity of neuropsychological tests. Only age predicted Vibratron score. Some tests were clearly inappropriate for use in developing countries. Neuropsychological tests were sensitive to educational level, age, alcohol consumption, and cultural indicators. The WHO tests in particular showed good construct validity for neuropsychological functions and should be more formally validated for use in developing countries. Nevertheless, a major problem of cultural dependence is evident for all neuropsychological tests used in this study, and methods for bypassing this problem in less developed settings are discussed.